Self-lubricating and draining, contacting face, rotating shaft seal

Abstract

A shaft seal assembly and method for pressure relief in a shaft seal assembly includes a stator having a static seal and a rotor rotatable relative to the stator that has a rotating seal. The static seal has an end face in sealing engagement with an end face of the rotating seal. At least one of the static seal and the rotating seal includes an annular passage defined in the respective end face and at least one axial passage extending through the respective seal. Lubricant drains and fills through the at least one axial passage and the annular passage at the sealing surfaces of the end faces. The end faces maintain sealing engagement during rotation of the rotor.

What is claimed is: 
     
       1. A shaft seal assembly comprising:
 a stator; 
 a rotor that rotates relative to the stator; 
 a rotating seal that rotates with the rotor; and 
 a static seal disposed in the stator, the static seal having an end face in sealing engagement with an end face of the rotating seal, wherein the end face of the static seal and the end face of the rotating seal are in contacting engagement during rotation of the rotating seal; and a spring that is adjacent the static seal and directly engages the static seal to bias the static seal against the rotating seal to maintain sealing engagement of the end faces by preventing axial movement of the rotating seal and the static seal during rotation of the rotating seal; wherein the static seal includes a first drain passage located at the contacting end faces, the drain passage being defined by at least one axial passage extending through the respective static seal and an annular passage defined in the respective end face, allowing a lubricant to drain and fill through the at least one axial passage and the annular passage at the sealing surfaces of the end faces, the end faces maintaining sealing engagement during rotation of the rotating seal; and 
 a second drain passage defined by a labyrinth formed in the rotor and an external drain port formed in the stator in communication with the labyrinth that maintain sealing engagement of the end faces by allowing contaminants to fall out of the shaft seal assembly. 
 
     
     
       2. The shaft seal assembly according to  claim 1  further comprising a biasing member, wherein the end faces are forced into sealing engagement at least in part by the biasing member. 
     
     
       3. The shaft seal assembly according to  claim 1 , wherein one of the end faces has a soft face and the other end face has a hard face. 
     
     
       4. The shaft seal assembly according to  claim 1 , wherein the static seal includes an annular groove in the end face and one or more axial openings extending through the static seal from the annular groove, whereby fluid flows through the one or more axial openings into the annular groove to lubricate the rotating seal. 
     
     
       5. The shaft seal assembly according to  claim 4 , wherein the one or more openings includes a plurality of circumferentially spaced openings defined in the static seal. 
     
     
       6. The shaft seal assembly according to  claim 2 , wherein the spring biasing member is a wave spring. 
     
     
       7. The seal member according to  claim 1  further comprising magnetic elements associated with each of the end faces, wherein one of the magnetic elements attracts the other. 
     
     
       8. The shaft seal assembly according to  claim 1  further comprising a static face carrier biased by a resilient member against the static seal to bias the static seal against the rotating seal. 
     
     
       9. The shaft seal assembly according to  claim 1 , wherein each of the static seal and the rotating seal has an annular passage. 
     
     
       10. The shaft seal assembly according  claim 1  further comprising a rotating face clamp, wherein the rotating seal is trapped between the rotor and the rotating face clamp. 
     
     
       11. The shaft seal assembly according to  claim 10  further comprising a fastener for securing the rotating face clamp to the rotor. 
     
     
       12. The shaft seal assembly according to  claim 1  further comprising a secondary seal for sealing the static seal relative to the stator, wherein the secondary seal is disposed in a seal groove in the static seal or stator. 
     
     
       13. The shaft seal assembly according to  claim 1 , wherein the static seal is biased against the rotating seal to maintain sealing engagement of the end faces by preventing axial movement of the rotating seal and the static seal during rotation of the rotating seal.